9/28/2015 What exactly is GSDIVA? How is it diagnosed? What - PDF document

9/28/2015 What exactly is GSDIVA? How is it diagnosed? What constitutes a normal test? GSDIVA: What are the optimal ages for GS Dog Inherited Ventricular Arrhythmias performing the Holter monitor? Signs and symptoms to watch for in the dog? Carl Sammarco, BVSc, MRCVS, Diplomate ACVIM (Cardiology) Will the pup outgrow the condition? carlsammarco@me.com cardiology@rbvh.com How is it genetically transmitted? Treatments for the condition? What exactly is GSDIVA? What exactly is GSDIVA? German Shepherd Dog Inherited Ventricular Arrhythmias or IVAGS Inherited Ventricular Arrhythmias of German Shepherd Other breeds? What exactly is GSDIVA? What exactly is GSDIVA? Ventricular Arrhythmia • ventricular extra or premature beats Ventricular Arrhythmias • Can be individual beats, pairs, triplets or runs of ventricular beats called salvos (short bursts) or sustained runs called ventricular tachycardia Normal Ventricular premature complexes (VPCs) IVAGS Ventricular Arrhythmias 1

9/28/2015 Ventricular Tachycardia Electrical System in heart - generates the ECG What exactly is GSDIVA? Sudden death typical only if VT What does that mean for the dog? VT = ventricular tachycardia • Sudden death typically occurs only in dogs with Ventricular Tachycardia • >10 runs @ >350 bpm = 50% sudden death • Dogs most commonly die suddenly at 7 months of age • No other clinical abnormalities are present. Arrhythmia is the Single ventricular premature complex VPC only one. • Dogs that die typically do not have structural changes • Arrhythmia due to change at cellular level with ion channels related to repolarization, K+ channel and Ca cycling. Plus heterogenous sympathetic innervation. What exactly is GSDIVA? What exactly is GSDIVA? What does that mean for the dog? What does that mean for the dog? • Sudden death typically occurs only in dogs with Ventricular • Sudden death typically occurs only in dogs with Ventricular Tachycardia Tachycardia • >10 runs @ >350 bpm = 50% sudden death • >10 runs @ >350 bpm = 50% sudden death • Dogs most commonly die suddenly at 7 months of age • Dogs most commonly die suddenly at 7 months of age • No other clinical abnormalities are present. Arrhythmia is the • No other clinical abnormalities are present. Arrhythmia is the only one. only one. • Dogs that die typically do not have structural changes • Dogs that die typically do not have structural changes • Arrhythmia due to change at cellular level with ion channels • Arrhythmia due to change at cellular level with ion channels related to repolarization, K + channel and Ca + cycling. Plus related to repolarization, K+ channel and Ca cycling. Plus heterogenous sympathetic innervation. heterogenous sympathetic innervation. 2

9/28/2015 What exactly is GSDIVA? How is it diagnosed? How is it diagnosed? What constitutes a normal test? What are the optimal ages for performing the Holter monitor? Signs and symptoms to watch for in the dog? Will the pup outgrow the condition? How is it genetically transmitted? Treatments for the condition? What exactly is GSDIVA? How is it diagnosed? How is it diagnosed? What constitutes a normal test? • VT is most often seen when at rest, or rapid eye movement sleep • During rest following excitement or exercise What are the optimal ages for performing the Holter monitor? Holter is a 24 hour recording of the ECG Signs and symptoms to watch for in the dog? Like minimum of 20 hours Will the pup outgrow the condition? How is it genetically transmitted? Treatments for the condition? What constitutes a normal test? What constitutes a normal test? In 24 hours: <50 ventricular premature beats is normal. 3

9/28/2015 Ventricular escape beats What constitutes a normal test? In 24 hours: <50 ventricular premature beats is normal. Between 50-60 beats, singles only is equivocal > 60 beats, especially with pairs or triplets, is abnormal Ventricular premature beat < 50 with pairs or triplets is equivocal Escape beats do not counts VPCs Abnormal Holter Abnormal Holter 73,000 VE, 3500 runs, longest 14, 6 months 195 singles, 7 months What exactly is GSDIVA? Abnormal Holter How is it diagnosed? What constitutes a normal test? What are the optimal ages for performing the Holter monitor? Signs and symptoms to watch for in the dog? Will the pup outgrow the condition? How is it genetically transmitted? Treatments for the condition? Used with permission, from anim mod spon arrhy death JCVElectph97 Moise 4

9/28/2015 What are the optimal ages for What are the optimal ages for performing the Holter monitor? performing the Holter monitor? • Sudden death can occur anytime between 3 to 18 months • Peak affected period appears to be 6-7 months. • Arrhythmias will start to decrease after a year of age and may be completely gone by 18-24 months. • Rare to have arrhythmias prior 3 months of age What exactly is GSDIVA? How is it diagnosed? What constitutes a normal test? What are the optimal ages for What are the optimal ages for performing the Holter monitor? performing the Holter monitor? Signs and symptoms to watch for in the dog? • Sudden death can occur anytime between 3 to 18 months Will the pup outgrow the condition? • Peak affected period appears to be 6-7 months. • Arrhythmias will start to decrease after a year of age and may be completely gone by 18-24 months. How is it genetically transmitted? • Rare to have arrhythmias prior 3 months of age Treatments for the condition? Ideal time if doing single Holter – 6-7 months of age Signs and symptoms to watch for in the dog? Signs and symptoms to watch for in the dog? • No other clinical abnormalities are present. Arrhythmia is the only one. 5

9/28/2015 What exactly is GSDIVA? How is it diagnosed? What constitutes a normal test? What are the optimal ages for performing the Holter monitor? Signs and symptoms to watch for in the dog? Will the pup outgrow the condition? Will the pup outgrow the condition? How is it genetically transmitted? Treatments for the condition? What exactly is GSDIVA? How is it diagnosed? What constitutes a normal test? What are the optimal ages for performing the Holter monitor? Signs and symptoms to watch for in the dog? Will the pup outgrow the condition? Will the pup outgrow the condition? • VA is rare to see after 24 months • Dogs reaching 2 years of age typically live normal life. How is it genetically transmitted? Treatments for the condition? • 3 traits for heritability: 1) single VPCs 2 ) couplets 3) 3 or more VE as VT • May be genetic variation for 3 traits • No simple recessive or dominant inheritance. No indication of sex bias. • Mildly affected dogs could produce dogs with VT. Matings between dogs with VT produced unaffected dogs, mild affected dogs and VT dogs • Breeding unaffected to affected produced full spectrum • One breeding of 2 unaffected dogs did not produce affected, but few pairings. • Heritability for affectedness is very high How is it genetically transmitted? How is it genetically transmitted? 6

9/28/2015 What exactly is GSDIVA? How is it diagnosed? What constitutes a normal test? What are the optimal ages for performing the Holter monitor? Signs and symptoms to watch for in the dog? Will the pup outgrow the condition? How is it genetically transmitted? Treatments for the condition? Treatments for the condition? • Medical therapy What exactly is GSDIVA? How is it diagnosed? • Sotalol • Amiodarone What constitutes a normal test? • Mexilitine/tocainide What are the optimal ages for performing the Holter monitor? • Proarrhythmia Signs and symptoms to watch for in the dog? • Pacemaker Will the pup outgrow the condition? • Defibrillator How is it genetically transmitted? • Nothing Treatments for the condition? Treatments for the condition? 7